This is an open, nonrandomized, rising dose, continuous infusion study in patients with recurrent or refractory solid malignancies. The study drug inhibits the enzyme farnesyl-protein transferase (FPT-ase) thus inhibiting the Ras pathway and subsequent cellular proliferation. L778123 has been developed as an FPT-ase inhibitor with an extended therapeutic index; the study will demonstrate whether it has utility in the treatment of cancer. It is hypothesized that L778123 steady-state plasma concentrations of at least 0.5 micro-mols will be generally safe and tolerable in patients. The study will determine the maximum tolerated dose, evaluate the safety and tolerability of the drug, and assess the pharmacokinetics of L778123.